Arc furnace with lift and swing aside roof



May 10, 1949. w. E. MOORE ARC FURNACE WITH LIFT AND SWING ASIDE ROOF 4 Sheets-Sheet 1 Filed Jan. 31, 1946 INVENTOR WLllzamli. Moore ATTORNEYS May 10, 1949. w. E. MOORE 2,469,740

ARC FURNACE WITH LIFT AND SWING ASIDE ROOF Filed Jan. 31, 1946 4 Sheets-Sheet 2 INVENTOR Wzlllz'am E Moore ATTORNEY S W. E. MOORE ARC FURNACE WITH LIFT AND SWING ASIDE ROOF May 10, 1949.

4 Sheets-Sheet 3 Filed Jan. 31, 1946 INVENTOR ATTORNEYS May 10, 1949. w. E. MOORE ARC FURNACE WITH LIFT AND SWING ASIDE ROOF Filed Jan. 31, 1946 4 Sheets-Sheet 4 i INVENTOR WLZlzamE More a J I ATTORNEYS PM an, 10, me

Aac sumac: wrrn ur'r asma William E. Moore, Fit

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Fa., a corporation of Delaware Application January 81, 10. Serial No. 644,582

scum, (01. 13-0) 1 This invention relates generally to an electric arc furnace and, more particularly. to an electric furnace having a roof of the lift-swing-aside type for top charging.

In the swing type of .top charge electric furnace, the roof and the supporting structure for the electrode masts are lifted and swung to the side by suitablepower means such as a vertical oil-hydraulic ram and cylinder, thereby uncovering the furnace crucible for charging purposes and the like.

In most top charge electric furnaces of the swing type, the means employed for causing sidewise movement or swing of the roof are generally complicated in design, expensive to manufacture, and rather diiiicult to maintain. This is primarily due to the fact that separate power actuators are used for effecting lifting of the roof and for effecting the swinging movement thereof, thus requiring careful attention and skill of the operator to coordinate these two movements.

An object of my invention is to provide an electric arc furnace of the swing type which is devoid of the above-named disadvantages of common types of such furnaces.

A more specific object of my invention is to provide a relatively simple and unitary poweractuator means for simultaneously efl'ecting a lifting and swinging movement of the roof and electrode supporting structure of an electric arc furnace and requiring no special skill or alertness by the operator to coordinate these two movements.

A still more specific object of my invention is to provide a novel hydraulic ram and cylinder construction for lifting the roof of an electric furnace which structure incorporates cam means to simultaneously cause sidewise swinging movement of the roof and the electrodesupporting structure as such roof is being lifted.

Other objects and advantages will become apparent from a study of the following specification and drawings wherein:

Figure 1 is a plan view of an electric furnace embodying the principles of my invention wherein the full lines show the roof in its normal position, whereas the dash and dot lines show the roof swung aside;

Figure 2 is a side elevation of the furnace shown in Fi ure l as viewed from a plane parallel to the tilting plane from the cylinder s de and showing the furnace in the upright position;

Figure 3 is a fragmentary cross-sectional view taken through the electrode gear and the furnace crucible at right angles to the tilting plane:

Figure 4 is an enlarged longitudinal sectional view of the ram and cylinder together with the associated structure shown broken away,

Figure 5 is a cross-sectional view taken along lines V-V of Figure 4; and

Figure 6 is a cross sectional view taken along lines VI-VI of Figure 4.

Referring more particularly to Figure l, numeral I denotes the roof of an electric furnace, which roof has rigidly secured thereto a roof ring or skewback I. The furnace roof is supported on cantilever or outrigger support beam I and 4 which are adiustably connected to the roof ring by suitable adjustable fastening means I, l, I and I, for example, in the form of screwthreaded collar and post assemblies as will appear more clearly in Figure 2.

As will appear more clearly in Figure 8, the furnace crucible comprises a shell I lined interna'lly with refractory material II. The roof i likewise is lined internally with refractory material II.

A cylinder I 2 is rigidly attached to the furnace shell 0 by means of brackets II and ii. A cylindrical shaped ram II is adapted to be lifted in cylinder I! by means of fluid or liquid pressure applied underneath the ram through port I! to effect lifting of the roof i. A collar iI, which carries a roller I1, is rigidly secured to the cylinder II. A column eye bracket I8 is rigidly secured to ram it by means of screws H (see Figure 4) and has attached thereto and depending therefrom a shroud is having a cam groove 20 adapted to cooperate with roller II. The roof i may be adjusted vertically with respect to eye bracket it by adjustable fastening means 5, 8. I and I.

In operation. it will be apparent that when ram or cylinder II with the attached shroud ll rises, the cam groove 20 moves up and around roller II, causing both lifting and swinging of the eye bracket II to one side carrying with it the roof and electrode gear so as to uncover the furnace crucible. The crucible may then be conveniently charged by means such as a drop-bottom bucket loaded with scrap or other melting material.

The furnace is mounted on rockers 2i and I! which roll on gear tracks II and 2, respectively, so as to be readily tiltable for tapping out the molten charge.

' The arcing electrodes 2!, it and l! are carried by means of arms 28, 28 and ll, respectively. mounted on top of electrode rams 8|, 82 and 33, respectively. These electrode rams slide aeoano in fluid pressure cylinders II, II and II. respectively. As will appear more clearly in Figure 4, cylinder I8 is concentric with and slidably mounted in cylinder i2 and serves as a ram for the roof as well as a container for the electrode ram 83.

The electrode rams II, I! and N are all supplied with fluid pressure in a conventional manner through flexible hose connections (not shown) so that in any position of the roof the rams are adjustably carried by the fluid pressure.

As stated previously, when cylinder i2 is fed with suitable pressure, ram ll lifts and thus lifts and swings the roof to one side. The three electrode rams contained in cylinders 34, SI and ii are adjusted as required by the electric power arcs in the furnace in any well known manner by intermittently applying fluid pressure to lift the rams and carry with them the electrodes and their mountings. The electrode rams being carried by the same eye bracket ll. maintain their relationship thereto whenever the roof of the furnace is lifted and swung.

Referring to Figure 4. the ram or cylinder i is packed in cylinder if by "chevron" packing or other suitable packing material OI held by a sealing ring N in any well known type of stuffing box. The ram 33 is similarly packed by means of a ring 54 and packing a in a conventional stuffing box as are the other similar rams 3i and 32. Ram or cylinder I! is guided within the bore of cylinder i! by means of slotted guides 39 and sliding on guideways II and 42. respectively,

so as to make it non-rotatable with respect to cylinder ii. in which it is further guided by means of bronze bushings 43.

The top end of electrode ram II as will appear in Figures 3 and 4 carries a bracket head ll, upon which is fastened a cradle ll for supporting arm II. which arm is water-cooled. At one end of arm 30 is supported a cylinder II which encloses a spring for normally urging lever 41 inwardly to cause a shoe or clamp ll to be pressed against electrode 11, so as to flrmly hold the electrode in a predetermined vertical position. Fluid pressure may be introduced in cylinder 46 on one side of a piston (not shown) to overcome the action of the spring so as to withdraw shoe 48 from electrode 21 to allow vertical adjustment of the electrode with respect to arm 10. The other electrode rams II and 32 carry similar electrode supporting structures as will be readily apparent from a study of Figures 1 and 3.

Two water core passages are provided, as shown in Figure 4, namely, II and i3. Passage ll is a water cored passage in the beam core supporting casting is through which water is circulated for cooling purposes. The annular water passage II is provided around the bezel ring 60 at the top of the furnace shell for conducting cooling water to prevent overheating in connection with the sand seal. The sand seal is provided by the bezel ring ll which provides an L-shaped annulus Ii around the top of the furnace which is fllled with sand or other refractory material into which the annular roof ring ii seats to make the joint flametight.

The specific structure of the electrode clamp and supporting means including the spring-operated, fluid pressure release cylinders, such as 48, forms the subject matter of my co-pendins application entitled Arc electrode support," filed January 31, 1946, under Serial No. 644,583.

In Figure l, the full lines show the roof and associated electrode-supporting structure in a normal position, whereas the dash and dot lines show these swung aside. likewise in Figure 2 the dash and dot lines show the electrode supporting arms in a lifted podtion. whereas the full lines show them in a lowered position.

Thusitwiilbeseenthatlhaveproyideda relatively simple mechanism for simultaneously swinging the roof and associated electrode-supporting structure aside as the roof is lifted by the ram. It will be apparent that the cam means for supporting structure is relatively simple in construction and foolproof in operation.

Also, it will be apparent that my invention is applicable to a furnace of the three electrode, three-phase type. or of the one electrode, singlephase type, or in fact, of any poly-phase type.

While I have illustrated and described a single embodiment of my invention, it will be understood that this is by way of illustration and that various changes and modifications may be made within the contemplation of my invention and within the scope of the following claims.

I claim:

1. An electric furnace of the top charge type including a crucible and roof and electrode supports, a ram cylinder rigidly secured to said crucible, a ram enclosed in said cylinder, bracket means rigidly secured to said ram for supporting said roof, said roof being liftable as the result of introduction of fluid in said cylinder beneath said ram, cam means associated with said cylinder to simultaneously effect sidewise swing of said roof during lifting thereof, said cam means including a depending skirt enshrouding said cylinder having a cammed groove and rigidly secured to said ram, a roller rigidly fastened to said cylinder and cooperable with said cammed groove to effect turning movement of said ram during reciprocation thereof, and said ram being hollow, a second ram slidably mounted in said first mentioned ram, and electrode support means mounted on said second ram.

2. An electric furnace of the top charge type including a crucible and a roof, bracket means secured to the walls of mo crucible, beams secured by said bracket means for supporting the roof, a plurality of load-sustaining members adjustable vertically and longitudinally between the beams and the roof a hollow cylinder rigidly secured to said bracket means, a hollow ram reciprocable in said cylinder, a bracket rigidly secured to said ram and supporting said roof, a second ram reciprocable in said hollow ram, an electrode holder rigidly secured to said second ram thereby allowing relative movement between said electrode holder and said hollow ram.

3. An electric furnace comprising a crucible and roof, cantilever means for supporting the roof, vertically and longitudinally adjustable tensioning means between the roof and supporting means a ram cylinder rigidly secured to an outer wall portion of said crucible, a hollow ram reciprocable in said cylinder as the result of introduction therebeneath of fluid pressure, an eye bracket rigidly secured to said ram and supporting said cantilever means, a second ram reciprocable in said hollow ram, an electrode support carried by said second ram, and guide means secured to the inner walls of said hollow ram to prevent turning movement of said hollow ram during reciprocation thereof.

4. In an electric furnace having a roof, a support for said roof, a fluid pressure cylinder connected to said roof support for elevating said support to raise said roof, an electrode support carried by said roof support. and a ram mounted concentrically within said cylinder and connected to the electrode support for moving said electrode support independently of said roof support.

5. In an electric furnace having a crucible and a roof therefor, a bracket supporting structure for said roof, a fluid pressure cylinder connected to the bracket supporting structure for actuating said bracket supporting structure to lift said roof with respect to said crucible, a plurality of electrode holders carried by said bracket supporting structure and movable therewith, fluid pressure operated rams connected to each of said electrode holders for operating each of said electrode holders independently of movement of said structure, and means mounting one of said fluid pressure operated rams concentrically of and within said cylinder.

6. In an electric furnace having a crucible and a roof therefor, a bracket supporting structure for said roof, a fluid pressure cylinder connected to said structure for actuating said bracket supporting structure to lift said roof with respect to said crucible, a plurality of electrode holders carried by said bracket supporting structure and movable therewith, means mounting each of said electrode holders on said bracket supporting structure including fluid pressure cylinders secured to and depending from said structure, and rams respectively in said last named cylinders and connected to said holders for moving said holders independently of movement of said supporting structure, and means mounting one of said last cylinders in said first fluid pressure cylinder whereby said one cylinder operates as a ram for effecting movement of said supporting structure.

7. In an electric furnace having a crucible and a roof therefor, a bracket supporting structure for said roof, a plurality of electrode holders, a plurality of fluid pressure cylinders secured to and depending from said structure, said cylinders occupying a position to one side of said crucible, a ram in each of said cylinders and connected to one of said holders for moving said holders independently of said supporting structure, and a stationary fluid pressure cylinder secured to the crucible in which one of said plurality of cylinders is mounted whereby said one cylinder operates as a ram for moving said supporting structure to move the roof and all of said electrode holders.

8. In an electric furnace having a crucible and a roof therefor, a bracket supporting structure for said roof, an electrode holder, a first fluid pressure cylinder positioned to one side of the crucible and secured to and depending from said structure, a ram in said cylinder and connected to said holder for moving said holder independ-' ently of movement of said structure, and a second fluid pressure cylinder mounted in a relatively flxed position, said flrst cylinder being mounted in said second cylinder whereby said first cylinder operates as a ram for moving said supporting structure.

9. In an electric furnace having a crucible and a roof therefor, an electrode movable relative to the furnace, a bracket supporting structure for the roof, an electrode holder, a fluid pressure cylinder fastened to said structure, a cylinder fixedly secured to said crucible and in which the fluid pressure cylinder is received, and a ram concentrically arranged inside said fluid pressure cylinder and connected to the electrode holder.

WILLIAM E. MOORE.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS 

